Effect of preadmission metformin use on clinical outcome of ARDS among critically ill patients with diabetes

Abstract

Introduction: Acute respiratory distress syndrome (ARDS) is related to high mortality and morbidity and is a major concern for critically ill patients, but there are currently no proven therapeutic measures to improve the clinical course of ARDS, except low tidal volume ventilation. Metformin is known to have pleiotropic effects including anti-inflammatory activity. In animal studies, metformin attenuated the severity of acute lung injury. Therefore, we hypothesized that preadmission metformin, which can show an anti-inflammatory effect, might alter the progress of ARDS among intensive care unit (ICU) patients with diabetes mellitus (DM).

Methods: We performed a retrospective cohort study of patients who were admitted to the medical ICU at Seoul National University Hospital because of ARDS from January 1, 2005 to April 30, 2015, and reviewed ARDS patients with DM. Metformin use was defined as prescribed within 3 months before admission. We analyzed 30-day mortality and severity of ARDS including PaO2/FiO2 ratio, lung injury score (LIS) and lung compliance after propensity score matching.

Results: Of 558 patients diagnosed as ARDS, 128 (23.3%) patients had diabetes and only 3 patients were treated with metformin monotherapy. Thirty patients received metformin in combination with other antidiabetic medications. Demographic characteristics, cause of ARDS, and comorbid conditions except chronic kidney disease were not different between metformin users and nonusers. Ventilator demand, hypoxemia index, extent of alveolar consolidation, and LIS were similar in both groups. The 30-day mortality was 42.42% in metformin users and 55.32% in metformin nonusers. On multivariable regression analysis, use of metformin showed trends to reduce a 30-day mortality, but this was not significant (adjusted -coefficient –0.19, 95% CI –1.76 to 1.39, P = .816). Propensity-score-matched analyses showed similar results.

Conclusions: Preadmission metformin use was not associated with reduced 30-day mortality among ARDS patients with DM in our medical ICU.